144Mhz DSB Micro Transceiver - This is my second 144 Mhz DSB transceiver, and is much closer to what I was looking to create, walkie talkie sized and runs on 9 volts. This design was very much influenced by the JR8DAG DSB walkie-talkies, and much to my surprise I think the 1N5711 diode detector performs better than my previous transistor design, it is also much less troublesome to get working. __ Designed by John Price VK3AJG

15M CW Transceiver Design - I've decided to design a new CW transceiver using some of the same design concepts employed in the highly successful 2N2/40 transceiver. The design goal of this rig is to provide a 15 meter CW rig that has good performance, while using discrete, readily available components whenever possible, including the venerable 2N2222 transistor, so that the rig can be reproduced in 3rd world countries by ham radio operators of modest means. __ Designed by Jim Kortge, K8IQY

20 Meter CW Transceiver - The 2N2/20 is the latest incarnation of the rather long list of 2N2/XX designs. Departures from the all "2N2222 transistor dictate" provided an opportunity to use a variety of discrete semicondutors to enhance performance. Within the iF chain, MPSH10 transistors were used, a J176 FET was used in the audio mute for very clean QSK keying, and a 2SC2166 final amplifier, used in the transmit strip allows the rig to put out about 7- watts. Commercial DBMs were also used to make construction easier for the beginning builder __ Designed by Jim Kortge, K8IQY

20 meters CW QRP Transceiver - The little QRP presented in this article may be built in a gradual manner, in fact it is divided in two main modules (plus VFO) , you may also complete only a single part (RX or TX module). Also the VFO module may be built with two complexity levels, as a conversion VFO or as a free oscillator, obtaining slightly different performances. __ Designed by Francesco Morgantini IK3OIL

20m SSB Transceiver, with DDS, PIC16, 10.7Mhz IF - My Radio amateur callsign is OZ2CPU. I like to use Atmel AVR Atmega PIC 16 PIC 16F876 PIC 16F84. Most electronics easy made for the novice and something is for the more experienced. __ Designed by Thomas Scherrer OZ2CPU

2N2222 40 Meter CW/DSB Tranceiver - in spring of 1998, NorCal sponsored a contest to design and build a project using no ICs and 22 or fewer 2N2222s as the active semiconductor devices. I thought this was a really intriguing idea, so I set about to design my version __ Designed by Monty Northrup

3.3V converter Delivers 3W from Li-Ion battery - 11/05/98 EDN-Design ideas (Several circuits here, scroll to find this one) Lithium-ion batteries are rapidly gaining popularity in portable applications because of their superior energy density, low self-discharge rate, and high cell voltage. When you use one Li-ion battery to power a 3.3V DC/DC converter; however, you encounter a problem, because the battery voltage. __ Circuit Design by David Salerno, Unitrode Corp, Merrimack, NH

30 Meter, Discrete Component CW Transceiver Built Manhattan-style - The 2N2/30 claims its heritage from the 2N2/XX platform, but also uses non-2N2222 transistor types and commercial mixers. From the beginning, it was to be a test bed for building with surface mount parts in a Manhattan-style construction environment. __ Designed by Jim Kortge, K8IQY

40 meter SSB QRP transceiver - in 1987 I built this radio. it has been published in a national ham radio magazine, and now finally found its way into the web! __ Designed by Manfred Mornhinweg

40 meters CW QRP Transceiver - This project describes a little QRP transceiver “full legal power” (5 W at 12 V) for the 40 meters band. The RiG may be built in a gradual manner, in fact it is divided in two main modules, or you may also complete only the RX module __ Designed by Francesco Morgantini IK3OIL

40 to 6 Meter "No Tune" Transverter - This project is a 40 meter to 6 meter CW "no tune" transverter using ten 2N2222 transistors and one 2N2907. The transverter requires 2 watts of drive from a 40 meter cw transceiver and outputs 2 watts on 6 meters. On receive, it uses the 40 meter rig as the intermediate frequency amplifier. its receive sensitivity is approximately 0.5 microvolts. Transmit spurious outputs are less than -50 dBc, meeting FCC spectral purity at a 2 watt power level. All transmit/receive switching is solid state. __ Designed by Jim Kortge, K8IQY

40/20 trap dipole - Portable 40/20 trap dipole - Here's an easy to make trap dipole for 40 and 20 meters. I made this for portable operations, mostly for "to the field" type QRP contests. Being able to switch bands between 20 and 40 quickly and without re-adjusting an antenna tuner is a nice feature. The only problem is it's a little heavy with the feed line and all, and putting it up in the raw New England woods can be daunting. __ Designed by Steven Weber, KD1JV

418/433 MHz short-range communication (Elektor Electronics article) - The history of licence-exempt use of radio transmitters started a few decades ago with the private use of low-power transmitters for radio-controlled models. Much later, CB radio in the 27-MHz band was legalised and type-approved radios for this band were freely available. __ Designed by Peter Jakab

49MHz Walkie Talkie - Lots of people are requesting walkie-talkie and RF remote control schematics, so here is some. Building se circuits needs special equipment and expertise in RF circuits. if you are going to experiment with se circuits, please note that I did not build __ Designed by Peter Jakab, Electrical Engineer, Engineer of Informatics

7MHz SSB Transceiver - Circuit diagram and brief description of 7MHz SSB Transceiver for Hams. The circuit is designed around two numbers of MC1496. it can push around 80 Watts with iRF840 in final. You can down load HTML version or printer friendly word document. __ Designed by Yujin Boby

5 Watt 80 Meter QRP CW Transceiver - A great deal of interest has been generated by my previous design articles, so I decided to go to work on a full blown transceiver design. After several months of work, the ROSE-80 transceiver was born. This transceiver is similar to other designs but contains some unique differences. This design boasts the following features __ Designed by Radio Amateur Society of Norwich

6m SSB & CW QRP transceiver - The concept of the 6m SSB & CW transceiver is similar to the 80m SSB & CW transceiver, described on this web site with some minor changes in AGC and audio PA. An additional RF preamplifier, which is not needed on 80m, has been added to get enough receiving sensitivity. The VFO is built as VCXO with frequency doubler, now. __ Designed by Aleksander Stare

6M Transverter - 17M to 6M transveter. __ Designed by EI9GQ homebrew radio

75 Meter SSB Transceiver - Here's 75 Meter QRP SSB Transceiver. in general, the transceiver switches the 4-element 1500 ohm xtal BPF ends between the inputs and outputs of the two SA602s to reverse the signal flow for R/T operation. Since no iF amplifier is used in the design, 20 dB of additional receiver gain is produced by the 2N2222 receiver RF amplifier, while automatic gain control (AGC) is produced by the peak DC swing of the LM386 output passed through a rectifier and filtered by a capacitor and fed to the gate of a BS170 enhancement mode FET acting as a variable resistor across the input of the LM386. Both receive and transmit band pass filtering are done by the same half-pI BPF. The diode pair in the mic circuit reduce the "chirp" that occurs during the R/T transition. Additional BS170s could easily be used to mute both the mic and audio instead of the R/T switch directly. These BS170s would be controlled by the +R and +T voltages on their gates while their drains would be tied to 1) the mic circuit between the two coupling capacitors and 2) pin number 1 (audio in) of the LM386 (BS170 sources to ground). Additional power output (perhaps 60 mW) could also be attained by connecting the RF output transistor's collector choke (10 uH) to a 9 V supply instead of the 5 V. Additional biasing current might also be required for this change.__

75M SSB rig with PTT - Nearly all the simple SSB rig designs you will find use relay or mechanical switches to go between receive and transmit. Relays use extra power and take up a fair amount of space. They can also be expensive. Mechanical switches don't use power, but also take up a fair amount of space and often have to be located in inconvenient mechanical locations to minimize lead lengths. They also make the rig harder to use. The solution is to use electronic switching. Often this is done with diodes or bi-directional amplifiers. Both of these approaches can get complicated. The approach used here is to use a 74HC5053 analog switch and it works well. Two sections of the analog SPDT switch are used to toggle the crystal filter between the inputs and outputs of SA612 mixers. The third section switches a by pass cap between the inputs of the mixers, depending in which direction their being used for. __ Designed by Steven Weber, KD1JV

7MHz SSB Transceiver - Circuit diagram and brief description of 7MHz SSB Transceiver for Hams. The circuit is designed around two numbers of MC1496. it can push around 80 Watts with iRF840 in final. You can down load HTML version or printer friendly word document. __ Designed by Yujin Boby

80 Meter, 5 Watt CW Transceiver - A great deal of interest has been generated by my previous design articles, so I decided to go to work on a full blown transceiver design. After several months of work, the ROSE-80 transceiver was born. This transceiver is similar to other designs but contains some unique differences. This design boasts the following features __ Designed by Radio Amateur Society of Norwich

80 Metre DSB Transceiver - The receiver is quite sensitive and tunes about 80-90Khz, tx output is ~300-500mW __ Designed by John Price VK3AJG

A 40 meter QRP-Transceiver - This was one of my very first transceiver developments. This page was also one of the very first circuit descriptions that I put on the internet quite some years agon. Today I would not build a transceiver like I did then, but it was working, so__

A unique PSK transceiver, Version 2 - NOTE: PA3CNO discovered and devised fixes for serveral problems with the design as discribed below. I will eventually include his modifications to this page, but for now please see his blog for details on the problems he found and his fixes. __ Designed by Steven Weber, KD1JV

AGC Circuit - SSB SSB Transceiver-Receiver Section: The AGC circuit uses a dual op-amp IC . The first stage amplifies the receive audio (taken from the hot side of the AF gain control). The output from this stage is converted to a DC (ish) signal by a voltage doubling rectifier. The final stage is a DC amplifier. A nice feature of the circuit, is that the meter is automatically set at zero, in the absence of any signal. I used an LF353 dual op-amp. Most fet input dual op-amps should work in this circuit, or you can use a pair of single op-amps. __ Designed by EI9GQ homebrew radio

An 80 meter rig for the MAS contest by KD1JV - Designed to be competative in the DL 80M "Mininum Art Session" contest, this rig features a crystal controlled 2W transmitter and a sensitive regenerative receiver, using 51 discrete parts on a 3.5" x 2.5" circuit board. __ Designed by Steven Weber, KD1JV

An automatically tuned HF Mobile antenna - This elegant design covers the complete spectrum from 7 to 30 MHz at less than 1.3:1 SWR, is compact, very weatherproof, robust and has good performance. This article was first published in the QEX / Communication Quarterly magazine. The article comes in five pages, with lots of photos, mechanical drawings, schematic diagram, PCB layout and software listing. Exact duplication is not for the faint of heart, but some of you may find individual parts and ideas useful for your own projects! __ Designed by Manfred Mornhinweg

Audio Amplifier - SSB Transceiver-Receiver Section: The AF amp has about 60 to 70 dB of gain. The transistor is a BC109C. I might try replacing it with a lower gain device. A typical 59+ signal, gives more than a volt pp at the collector. The power amplifier IC is an LM380N (14 pin version). if you intend to use the rig on CW, the LM380N must be powered up on transmit as well as receive (for the sidetone osc.). __ Designed by EI9GQ homebrew radio

Balanced Modulator - The simple, two diode balanced modulator is still one of the best ways of generating a DSB/SSB signal. You can use Silicon switching diodes, 1N914, 1N4148, Germanium point contact diodes, 1N34, or Schottky (Hot Carrier) diodes. I used a pair of 1N34's. You should spend a few minutes with a fistful of diodes and a multi-meter to find a pair that are well matched for forward and reverse resistance. Both transistors are BC548's, for the reasons mentioned above. __ Designed by EI9GQ homebrew radio

BC547 80M SSB QRP Transceiver - This is a bit of a retro design, and uses easily obtained parts, no hard to find or expensive IC 's (no IC 's at all) __ Designed by John Price VK3AJG

BPF and Mixer - SSB Transceiver-Receiver Section: The signal from the RX/TX relay is filtered by an 80Mtr band pass filter. This can be replaced by a filter for another band or a bank of switched filters, for a multI band rig. if you need to cover from 3.5 to 4.0 MHz, you will need to replace the 10p coupling capacitor with one of a larger value (about 18p). You can wind your own inductors, about 18 turns on a 10K type Toko former will have 5.5 microhenries of inductance. __ Designed by EI9GQ homebrew radio

Exciter for SSB Tranceiver - Now that people are getting married, and having babies on the internet, isn't it about time someone designed and built an SSB rig on the net?. The rig will be built up from various modules, starting with the SSB exciter board. The first prototype board has been built and tested on the bench but not on air. The resulting SSB signal looks good on the scope, and sounds ok on a monitor receiver. __ Designed by EI9GQ homebrew radio

Fairly Simple Circuit 75M SSB rig with PTT - Nearly all the simple SSB rig designs you will find use relay or mechanical switches to go between receive and transmit. Relays use extra power and take up a fair amount of space. They can also be expensive. Mechanical switches don't use power, but also take up a fair amount of space and often have to be located in inconvenient mechanical locations to minimize lead lengths. They also make the rig harder to use. The solution is to use electronic switching. Often this is done with diodes or bi-directional amplifiers. Both of these approaches can get complicated. The approach used here is to use a 74HC5053 analog switch and it works well. Two sections of the analog SPDT switch are used to toggle the crystal filter between the inputs and outputs of SA612 mixers. The third section switches a by pass cap between the inputs of the mixers, depending in which direction their being used for. __ Designed by Steven Weber, KD1JV